1. Field of the Invention
The present invention relates to an air conditioner instructed to operate with a remote control unit, said air conditioner having a liquid crystal display on an indoor unit thereof.
2. Description of the Prior Art
A separation-type air conditioner comprises an indoor unit placed on the wall of a room to be air-conditioned and an outdoor unit placed outdoors.
Moreover, some air conditioners employ an indoor unit and an outdoor unit that are integral with each other. Such integral-type air conditioners are provided with an indoor unit and an outdoor unit that are installed on the indoor and outdoor sides, respectively, of an opening formed in a wall or a window.
In the following descriptions, an indoor unit of a separation-type air conditioner will be presented. However, it should be noted that the indoor unit of the present invention is not limited to the indoor unit of a separation-type air conditioner, but is applicable also to the indoor-side configuration of an integral-type air conditioner.
FIG. 1 is an exterior view showing an indoor unit of a typical separation-type air conditioner. On the indoor unit 1, a liquid crystal display 5 for displaying various pieces of information is disposed in the vicinity of an air outlet 4 incorporating an up-and-down wind direction louver 3. The operation of the air conditioner is controlled by a microcomputer being incorporated. By the user operating a remote control unit 2, a signal instructing the air conditioner to operate is transmitted to the microcomputer.
FIG. 2 is an exploded perspective view of the liquid crystal display 5. Reference numeral 6 represents a liquid crystal panel for displaying letters and symbols. Reference numeral 7 represents a backlight for illuminating the liquid crystal panel 6 from behind so that the display becomes clear. The backlight 7 comprises a plurality of light emitting diodes (LEDs). Reference numeral 8 represents a unit cover for covering the backlight 7. The unit cover 8 uniformizes the illumination light incident on the liquid crystal panel 6.
FIG. 3 is a front view of the remote control unit 2. The remote control unit 2 has, as operation buttons, a start/stop button 2a for starting and stopping the air conditioner, a temperature setting button 2b for increasing and decreasing the set temperature, an operation start timer button 2c, and a light adjustment button 2d. A liquid crystal display 2e is also provided for displaying the contents of signals transmitted by the operation buttons 2a, 2b, 2c and 2d and various pieces of information.
Problems of the conventional air conditioner having the above-described structure will be described.
First, a first problem will be described. FIG. 4 shows the arrangement of a circuit for controlling the liquid crystal display 5. An IC driver circuit 9 has a contrast fine adjustment possible circuit (not shown), and the liquid crystal display 5 is connected thereto by a signal line 10. A thermistor 11 detects a subtle change in ambient temperature and inputs the detected change to the IC driver circuit 9. The contrast fine adjustment possible circuit controls the contrast of the liquid crystal panel 6 of the liquid crystal display 5 based on the input signal from the thermistor 11. However, since the liquid crystal display 5 is situated in the vicinity of the air outlet 4, the ambient temperature drastically changes while air conditioning is being performed. Therefore, the control of the liquid crystal panel 6 by the contrast fine adjustment possible circuit cannot follow the temperature change, so that the contrast cannot sufficiently be adjusted.
Next, a second problem will be described. There are cases where the display on the liquid crystal display 5 cannot clearly be viewed by the user according to the position of placement of the indoor unit 1. In such cases, according to the prior art, the remote control unit 2 is operated to adjust the light quantity of the backlight 7. However, this is insufficient to improve the viewability of the liquid crystal display 5.
Next, a third problem will be described. When the room air is dirty, it is desirable for the air conditioner to perform an air-cleaning operation or a ventilating operation. When the humidity in the room becomes low or high, it is desirable to perform a humidifying operation or a dehumidifying operation. However, to perform these operations, it is necessary for the user himself or herself to notice the condition of the room air.
Next, a fourth problem will be described. When the air conditioner is out of order, it does not operate even though the user instructs it to operate. When the user instructs the air conditioner to perform an operation while the air conditioner is performing another operation, there are cases where the air conditioner cannot perform the operation it is instructed to perform. For example, while the air conditioner is performing a defrosting operation, it cannot perform a heating operation even though it is instructed to do so. In such cases, the conventional air conditioner provides the user with no notification. Consequently, every time this happens, unnecessary worry and confusion are caused to the user.
Next, a fifth problem will be described. When the air conditioner is operated with the operation start timer, a warm-up operation is typically performed before the air conditioner starts to operate. In the conventional air conditioner, the backlight 7 of the liquid crystal display 5 is turned on at the start of the warm-up operation. However, when the operation start time is set in accordance with the time when the user gets up or the time when the user comes home, it is a waste of power that the backlight 7 is on during the warm-up operation. Particularly, when the operation start time is set at the time when the user gets up, turning on of the backlight 7 before the operation start time sometimes awakens the user unpleasantly.
An object of the present invention is to provide an air conditioner in which a desirable display is provided on the liquid crystal display of the indoor unit.
To achieve the above-mentioned object, an air conditioner of the present invention is provided with: an indoor unit; a liquid crystal display provided on the indoor unit for displaying various pieces of information; and a remote control unit for transmitting a signal to instruct the air conditioner to operate. Here, contrast of a display on the liquid crystal display is adjustable by operating the remote control unit.
Another air conditioner of the present invention is provided with: an indoor unit; a liquid crystal display provided on the indoor unit for displaying various pieces of information; a backlight provided on the liquid crystal display for illuminating a display on the liquid crystal display; at least one of an air cleaner, a ventilator, a dehumidifier and a humidifier; and at least one of contamination detecting means for detecting contamination of room air and humidity detecting means for detecting humidity of room air. Here, when the contamination detecting means detects contamination of the room air, a notification display urging the air cleaner or the ventilator to operate is provided on the liquid crystal display, or when the humidity detecting means detects that humidity of the room air is high, a notification display urging the dehumidifier to operate is provided, or when the humidity detecting means detects that the room air is dry, a notification display urging the humidifier to operate is provided, and the backlight is lit in a color different from a color for a normal display.
Yet another air conditioner of the present invention is provided with: an indoor unit; a liquid crystal display provided on the indoor unit for displaying various pieces of information; and a backlight provided on the liquid crystal display for illuminating a display on the liquid crystal display; and at least one of abnormality detecting means for detecting a failure and an abnormality of the air conditioner and operation condition detecting means for detecting that an operation the air conditioner is instructed to perform cannot be performed. Here, when the abnormality detecting means detects a failure of the air conditioner, a notification display indicating that a failure occurs is provided or when the operation condition detecting means detects that an operation the air conditioner is instructed to perform cannot be performed, a notification display indicating that the operation cannot be performed is provided, and the backlight is lit in a color different from a color for normal display.
Still another air conditioner of the present invention is provided with: an indoor unit; a liquid crystal display provided on the indoor unit for displaying various pieces of information; and a backlight provided on the liquid crystal display for illuminating a display on the liquid crystal display; a remote control unit for transmitting to a control unit a signal to instruct the air conditioner to operate and a signal to turn on or off the backlight; and a timer for causing the air conditioner to start to operate at a set time. Here, when an operation start time of the air conditioner is set with the timer, the backlight is off during a warm-up operation performed before the air conditioner starts to operate, and when the air conditioner starts to operate, the backlight is turned on.